Wyclif and Lollardy
Wyclif is widely known for attacking the Renaissance Papacy and believed that, once one examined scripture, they held no power. He stated that they should be removed from power and he disagreed with many of their practices such as pilgrimages, the veneration of saints, and he greatly opposed the corruption of the clergy. Many of the people in Renaissance Europe agreed with Wyclif and began to follow him and his beliefs. These people are known as Lollards.
Hus and the Hussites
The beliefs of Wyclif made their way into Bohemia and were readily excepted, as the Church was already widely criticized. John Hus (1374-1415) was a great supporter of Wyclif's beliefs and also believed that the Church was corrupt and had too much power. The Church couldn't handle the bad publicity that Hus was giving them and decided to try him at the Council of Constance. He was promised safe passage, but was instead arrested and condemned. Afterwards he was burned at the stake, an event that sparked the Hussite wars that decimated the Holy Roman Empire. Peace was finally made in 1436.
Reform of the Church
Following in the footsteps of John Hus, the Council of Constance was able to pass two different decrees against the Church. The first, the Sacrosancta, stated that the general church council strictly received power from God. The second decree, the Frequens, required the regular holding of general councils, so that the clergy could stay on track. These two decrees, however, did nothing in the long run as the popes were able to pass the appealing to the church council as heretical. Afterwards the popes were able to restore their power within the Church, but not within society. Unlike the popes of the Medieval times, they no longer had power over monarchies, governments, kings etc.